AD7781BRZ: 20-Bit, Pin-Programmable, Ultralow Power Sigma-Delta ADC
The AD7781 is a complete low power front-end solution for bridge sensor products, including weigh scales, strain gages, and pressure sensors. It contains a precision low power 20-bit sigma-delta (Σ-Δ) ADC, an on-chip, low noise programmable gain amplifier (PGA), and an on-chip oscillator.
Consuming only 330 μA, the AD7781 is particularly suitable for portable or battery-operated products where very low power is required. The AD7781 also has a power-down mode that allows the user to switch off the power to the bridge sensor and power down the AD7781 when not converting, thus increasing the battery life of the product.
For ease of use, all the features of the AD7781 are controlled by dedicated pins. Each time that a data read occurs, eight status bits are appended to the 20-bit conversion. These status bits contain a pattern sequence that can be used to confirm the validity of the serial transfer.
The on-chip PGA has a gain of 1 or 128, supporting a full-scale differential input of ±5 V or ±39 mV. The device has two filter response options. The filter response at the 16.7 Hz update rate provides superior dynamic performance. The settling time is 120 ms at this update rate. At the 10 Hz update rate, the filter response provides better than -45 dB of stop-band attenuation. In load cell applications, this stop-band rejection is useful to reject low frequency mechanical vibrations of the load cell. The settling time is 300 ms at this update rate. Simultaneous 50 Hz/60 Hz rejection occurs at both the 10 Hz and 16.7 Hz update rates.
The AD7781 operates with a power supply from 2.7 V to 5.25 V. It is available in a narrow body, 14-lead SOIC package and in a 16-lead TSSOP package.
Applications
- Weigh scales
- Pressure measurement
- Industrial process control
- Portable instrumentation
AD7781BRZ 特点
- Pin-programmable filter response
Update rate: 10 Hz or 16.7 Hz - Pin-programmable in-amp gain
- Pin-programmable power-down and reset
- Status function
- Internal clock oscillator
- Internal bridge power-down switch
- Current:
115 μA typical (Gain = 1)
330 μA typical (Gain = 128) - Simultaneous 50 Hz/60 Hz rejection
- Please see data sheet for additional features
AD7781BRZ 功能框图
| 产品型号 | 产品状态 | 封装 | 引脚 | 温度范围 |
|---|---|---|---|---|
| AD7781BRUZ | 量产 | 16 ld TSSOP | 16 | 工业 |
| AD7781BRUZ-REEL | 量产 | 16 ld TSSOP | 16 | 工业 |
| AD7781BRZ | 量产 | 14 ld SOIC | 14 | 工业 |
| AD7781BRZ-REEL | 量产 | 14 ld SOIC | 14 | 工业 |
| AD7781CRUZ | 量产 | 16 ld TSSOP | 16 | 工业 |
| AD7781CRUZ-REEL | 量产 | 16 ld TSSOP | 16 | 工业 |
| AD7781CRZ | 量产 | 14 ld SOIC | 14 | 工业 |
| AD7781CRZ-REEL | 量产 | 14 ld SOIC | 14 | 工业 |
AD7781BRZ 应用技术支持与电子电路设计开发资源下载
- AD7781 数据手册DataSheet下载. pdf
- Analog Devices, Inc.ADI 美国模拟器件公司产品订购手册 .PDF
- ADC模数转换器选型指南 . PDF